Airfoils are found in many different shapes, sizes and functions in the aircraft and related arts. The Wright brothers, Orville and Wilbur, are for example known to have devoted extensive time to the achieving of a surprisingly efficient airfoil cross section for the propellers used on their early 1900's flyers. Airfoil shapes are of course also found in aircraft wing cross sections, in tail assemblies and in helicopter rotors as a short list of examples. Each of these airfoils involves a compromise between the achieved lift and drag characteristics of the selected shape. The results of sharply differing compromises in this area may be appreciated to some small degree by consideration of the differing wing designs used in the World War II U.S. bomber aircraft known as the B-17 and the B-24. The B-17 wing is or was of a large and long cross sectional shape and resulted in what was considered a tolerant and forgiving airfoil while the B-24 wing was considerably smaller yet capable of lifting a significantly larger aircraft payload but also was less tolerant of marginal flight conditions.
In many airfoil arrangements the achieved overall performance can be improved by way of drag reduction; a reduction accomplished through consideration of boundary layer air flow conditions between the wing surface and the surrounding air. The introduction of small boundary layer air or gas flows into this area of transition is one tool that is found useful in achieving better airfoil performance. Such boundary layer air or gas flows may be realized in a variety of ways including use of pressurized air dispensers and with use of plasma generating apparatus, apparatus in which a relatively small amount of ionized ambient fluid or air is introduced into the airfoil transition area by way of electrical plasma generating elements disposed at a selected location along the air flow path of the airfoil. For present purposes such an electrical apparatus will be discussed using the formal name of “single dielectric barrier aerodynamic plasma actuator”. In the present invention the mechanism for generating this plasma is recognized to be that of the dielectric barrier electrical discharge notwithstanding the views of accomplished others working in this art that some differing plasma generating mechanism is involved.